“…The intestinal glands extend downward from the epithelial cell surface and are usually simple, unbranched tubules composed mainly of mucus cells and smaller absorptive, endocrine and undifferentiated cells. The glands are known for secreting digestive fluids into the alimentary canal [ 24 ]. Compared with that of IRs and INRs, the intestinal glands arrangement in HCs appeared relatively tight ( Fig.…”